Throw error messages in the functions

Throw error and warning messages in the particular methods, not
in the check_binary method. Now it's in compliance with the rest
of the checks.

Add docstrings and use better names for variables (we don't want
to have one-letter names).

rpmlint/checks/FHSCheck.py

@@ -6,6 +6,12 @@ from rpmlint.checks.AbstractCheck import AbstractCheck
 class FHSCheck(AbstractCheck):
     """
     Validate that binary files are packaged according to FHS.
+
+    We follow FHS 3.0 specification that can be found at
+    http://refspecs.linuxfoundation.org/FHS_3.0/fhs-3.0.pdf
+
+    usr_subdir lists allowed directories in /usr (FHS chapter 4.2 and 4.3)
+    var_subdir lists allowed directories in /var (FHS chapter 5.2 and 5.3)
     """
     usr_regex = re.compile('^/usr/([^/]+)')
     usr_subdir = ('X11R6', 'bin', 'games', 'include', 'lib', 'lib64',
@@ -24,49 +30,59 @@ class FHSCheck(AbstractCheck):
         usr_list = []
 
         for fname in pkg.files:
-            s = FHSCheck.usr_regex.search(fname)
-            if s:
-                d = s.group(1)
-                if not self._check_usr_std_dir(d, usr_list):
-                    self.output.add_info('W', pkg, 'non-standard-dir-in-usr', d)
-            else:
-                s = FHSCheck.var_regex.search(fname)
-                if s:
-                    d = s.group(1)
-                    if not self._check_var_FSSTND_dir(d, var_list):
-                        self.output.add_info('W', pkg, 'FSSTND-dir-in-var', d)
-                    elif not self._check_var_std_dir(s, var_list):
-                        self.output.add_info('W', pkg, 'non-standard-dir-in-var', d)
+            usr_path = self.usr_regex.search(fname)
+            if usr_path:
+                # Run tests for /usr directory
+                usr_file = usr_path.group(1)
+                self._check_usr_standard_dir(usr_file, pkg, usr_list)
+                continue
 
-    @staticmethod
-    def _check_usr_std_dir(d, usr_list):
+            var_path = self.var_regex.search(fname)
+            if var_path:
+                # Run tests for /var directory
+                var_file = var_path.group(1)
+                self._check_var_FSSTND_dir(var_file, pkg, var_list)
+                self._check_var_standard_dir(var_file, pkg, var_list)
+
+    def _check_usr_standard_dir(self, usr_file, pkg, usr_list):
         """
         Check if the file is in valid subdirectory of /usr.
-        """
-        if d not in FHSCheck.usr_subdir and d not in usr_list:
-            usr_list.append(d)
-            return False
-        return True
 
-    @staticmethod
-    def _check_var_FSSTND_dir(d, var_list):
-        """
-        Check if the file is not packaged in an obsolete (illegal) subdirectory of /var.
-        """
-        if d in FHSCheck.var_fsstnd and d not in var_list:
-            var_list.append(d)
-            return False
-        return True
+        FHS 3.0 says: "Large software packages must not use a direct
+        subdirectory under the /usr hierarchy." Check if this package contains
+        a directory in /usr that is not mentioned in FHS (usr_list).
 
-    @staticmethod
-    def _check_var_std_dir(d, var_list):
+        Refer to http://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch04.html for
+        details.
+        """
+        if usr_file not in FHSCheck.usr_subdir and usr_file not in usr_list:
+            usr_list.append(usr_file)
+            self.output.add_info('W', pkg, 'non-standard-dir-in-usr', usr_file)
+
+    def _check_var_FSSTND_dir(self, var_file, pkg, var_list):
+        """
+        Check if the file is not packaged in an obsolete (illegal)
+        subdirectory of /var.
+        """
+        if var_file in FHSCheck.var_fsstnd and var_file not in var_list:
+            var_list.append(var_file)
+            self.output.add_info('W', pkg, 'FSSTND-dir-in-var', var_file)
+
+    def _check_var_standard_dir(self, var_file, pkg, var_list):
         """
         Check if the file is in valid subdirectory of /var.
+
+        FHS 3.0 says: "Applications must generally not add directories to the
+        top level of /var. Such directories should only be added if they have
+        some system-wide implication, and in consultation with the FHS
+        mailing list."
+
+        Refer to http://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch05.htm
+        for details.
         """
-        if d not in FHSCheck.var_subdir and d not in var_list:
-            var_list.append(d)
-            return False
-        return True
+        if var_file not in FHSCheck.var_subdir and var_file not in var_list:
+            var_list.append(var_file)
+            self.output.add_info('W', pkg, 'non-standard-dir-in-var', var_file)
 
 
 fhs_details_dict = {